Snap action switch



March 15, 1960 H. E. PAYNE SNAP ACTION swrrcu Filed Feb. 20. 195'? w 7JZWIE. y

INVENTOR. H6. PiY Vi HYVWZJYZ'F' SNAP ACTION SWITCH Harold E. Payne,Clark, NJ.

Application February 20, 1957, Serial No. 641,313

' 3 Claims. (Cl. 200-122 This invention relates to a type of relay, morespecif ically to a snap action switch whereby a sharp making andbreaking of the circuits involved is obtained.

In the past many devices have been designed to accomplish the result ofmaking or breaking circuits. However, these sulfered from certaindisadvantages, such as for example undue complexity, sensitivity toshock and inability to function after the casing has been deformed.

It is among the objects of this invention to provide an accuratesensitive relay, which is of fairly simple construction.

It is also among the objects of this invention to provide a relay whichis rugged and shock-resistant.

It is further among the objects of this invention to provide a relaywhich will be operable even though the easing into which it fits issubstantially deformed.

In practicing this invention there is provided a base carrying asupporting means consisting of, in one form of the invention, twoelements which are fastened at their lower ends to thesaid base andafiixed to each other at their upper ends. In the preferred form of theinvention, one element is a rod or channel while the other is composedof two vertical side members spaced apart horizontally and connected attheir upper ends by a horizontal cross piece. The aforementioned rod orchannel is rigidly connected to the cross piece at a point between theside pieces.

Beneath the cross piece and substantially between the side pieces isplaced a rod having means for heating thereof associated with it. Thelower end of the heated rod is fixed to the base and the upper end isaflixed to a bar depending from the supporting means. In the preferredform of the invention, the heating means comprises a coil of resistancewire winding around the rod and connected to a source of electricalcurrent.

Also depending from the supporting means is a yoke carrying a contactlocated preferably near the lower end thereof and which is connected tothe bar by means of a spring. The spring comprises a curved strip havingone end fixed to the bar and the other end affixed to the yoke so thatmovement of the bar in one direction causes snap action movement of theyoke in the opposite direction.

On either side of the contact mounted on the yoke are placed twostationary contacts which are so positioned that the movable contactcloses a circuit including one or the other, depending upon whichposition the yoke is in.

In operation, the movable contact is biased so that it touches one ofthe two stationary contacts. Electrical current flowing through the coilaround the heated rod causes the temperature of the rod to rise, thusresulting in a linear expansion thereof. The depending bar is springbiased to the left (as shown in Fig. 2) and is restrained by the rod.Consequently, the rod is always under tension. and. when it is heated.permits the bar to move relative to the stationary members of the relay.When the lower end of the bar has reached a point over center, theaction of the spring causes the yoke to move United States Patent2,928,918 Patented Mar. 15, 1960 ice abruptly in a direction opposite tothat taken by the bar. This causes the movable contact to break thecircuit formed prior to the heating of the rod and to make contact withthe contact point on the other side, thus opening one circuit andclosing another.

In the accompanying drawings constituting a part hereof and in whichlike reference characters indicate like parts,

Fig. l is a perspective view of one form of relay mad according to thisinvention;

Fig. 2 is a view along line 2-2 of Fig. 1, some parts being omitted forclarity;

Fig. 3 is a sectional view along line 3-3 of Fig. 2, some parts beingomitted for clarity, and

Fig. 4 is an enlarged fragmentary view of the end of the bar, the springand the lower end of the yoke, showing the contact.

Referring particularly to Figs. 1 and 2, there is provided a base 1, acasing 2 of any suitable material mounted thereon, prongs 4 extendingbelow base 1 and having portions 3 extending above base 1 for thepurpose of connection with the elements of the relay structure. Thesupporting means for the structure as a whole is composed of an element5 having two substantially vertical side pieces 7, an upper cross bar 6and a lower cross bar and bracket 8, which serves not only to steadysuspending member 5 but also to support heated rod 9. The remainder ofthe supporting means consists of a channel 13 which is secured to crossbar 6. Rod 9 carrying coiled wire 10 is fixed at 11 to member 24 whichin turn is fixed to bar 12 which depends from cross bar 6. This providesa connection between the upper end 11 of rod 9 and depending bar 12.Depending from channel 13 is yoke 14 carrying at its lower end movablecontact 15. Yoke 14 is provided with a tongue 25 which is inserted intoa slot in spring 18. A similar tongue 26 on the lower end of bar 12 isinserted into the other end of spring 18.

Stationary contacts 16 and 17 are positioned so that the movement ofyoke 14 will carry contact 15 from one to the other. Stationary contacts16 and 17 are connected to appropriate terminals 3 by electricalconductors 19 and 20, respectively.

There is provided on channel 13 an adjusting screw 22 mounted in aspring member 23, which member carries yoke 14. By adjusting screw 22,the position of the upper end of yoke 14 is altered. This permitsadjustment of the amount of linear expansion or contraction of rod 9necessary to cause the mechanism to trip.

In operation an electrical current passing through prongs 4, terminals 3into coil 10 causes rod 9 to rise in temperature and expandlongitudinally. This causes upper end 11 of rod 9 to move upward,permitting spring biased depending bar 12 to move to the left, which inturn causes yoke 14 to move to the right as shown in Fig. 2. Thusmovable contact 15 snaps from stationary contact 17 to stationarycontact 16, thus breaking one circuit and closing another.

Although only one form of this invention has been specificallydescribed, nevertheless it is possible to make numerous changes such aswould be apparent to one skilled in the art without departing from thescope thereof. For example, almost any form of supporting means may beused to hold the structure in place with the proviso that it notinterfere with the necessary movement of the nonstationary elements.Further, electrical insulation may be provided at certain of theterminals 3 or at other places in the device wherever it is desired toprevent the flow of current.

Still further it is possible to arrange spring 18 so that its curvatureis in the horizontal rather than vertical plane,

0 with a corresponding adjustment in the proportions of depending bar 12and yoke 14. In addition, rod 9 may be heated by any suitable meanswhether it be an internal coil or simply the passage of electric currentthrough the rod itself. It is possible to manufacture rod 9 of suchresistance material that it will generate sufiicient heat for controlpurposes without the necessity of a coil or wire.

These and other changes in the details of the invention may be madewithout departing from the principles herein set forth, and theinvention is therefore to be broadly construed and not to be limitedexcept by the character of the claims appended hereto.

Iclaim:

l. A snap action switch comprising a a base, supporting means, a rodhaving means for controlled heating 'thereof, said means for heatingconsisting of a coil of wire wound around said rod and connected to asource of electric current of suitable voltage and amperage, a bardepending from said supporting means, the upper end yoke, at least oneadditional contact, said contacts adapted to make and break at least oneelectrical circuit.

2. A snap action switch according to claim 1 wherein the springconnection is a curved strip having one end afiixed to said bar and theother end atfixed to said yoke so that movement of said bar in onedirection causes movement of said yoke in the opposite direction.

3. A snap action switch according to claim 1 wherein there are twoadditional contacts so positioned that the contact on said yokereciprocates between said additional contacts alternately closing onecircuit and opening the other.

References Cited in the file of this patent UNITED STATES PATENTS914,684 Warner Mar. 9, 1909 1,215,665 Landis Feb. 15, 1917 2,218,908Fonseca Oct. 22, 1940 2,429,074 Rugh Oct. 14, 1947 2,700,084 BroekhuysenJan. 18, 1955 2,769,890 'Hallerberg et a1. Nov. 6, 1956

